The present invention relates to a method and apparatus for producing double conically-shaped springs or the like from heated rods. The shaping of the article is produced in several steps, and apparatus is provided for carrying out the method.
There is described in the German patent reference DE-OS 23 30 208, a method for producing an article of the foregoing species for taking advantage of hot-forming in relation to the known cold-forming of the article. In this arrangement, the spring is first wound on a mandrel corresponding to the smallest internal diameter of the spring. The spring is thus wound in a cylindrical manner. Thereafter, in a second step, the windings are brought to a larger diameter by winding back, on a hollow form.
Such a process cannot be carried out on conventional winding apparatus for machines, and leads to particular difficulties when extremely small spring diameters are used at the spring ends. Difficulties are also incurred in the shaping procedure, whereby the springs may be additionally damaged. There is also required a relatively large and complex amount of equipment, as well as fabrication time.
Accordingly, it is an object of the present invention to provide a method and apparatus through which any winding diameter can be produced and conventional manufacturing elements can be used for the fabrication processes.
Another object of the present invention is to provide an arrangement of the foregoing character which is substantially simple in construction and may be economically assembled.
A further object of the present invention is to provide an arrangement, as described, which may be easily maintained in service and which has a substantially long operating life.